1. Observations of High Frequency GWs observed in mesospheric airglow, and the implication to the GW imposed zonal stress and the residual circulation
Gary R. Swenson1, Fabio Vargas1, Alan Liu2, Xian Lu3, Zhenhua Li3, Chester Gardner1
Electrical and Computer Engineering, University of Illinois, Urbana, IL, United States.
Physical Sciences, Embry Riddle Aeronautical University, Daytona Beach, FL, United States.
Atmospheric Sciences, University of Illinois, Urbana, IL, United States.

2. OH emission altitudes]
Introduction
The background atmosphere and meridional circulation
OH and mesospheric airglows, and altitude weighting functions, I’/I
Directional statistics, and methods
[Globally, the meridional component is toward the summer pole, at
OH emission altitudes]
Momentum flux, methods of determination from airglow
Freely propagating versus damped
Momentum flux, statistical summary from a Brazilian study
Summary

3. The Lower and Middle Atmosphere10 20 30 40 50 60 70 80 90 km
270
1013 55 11 3
0.7
0.2
0.05
0.009
0.003
Pres
(mbar)
Equator
Pole
(WINTER)
(SUMMER)
Created by A. J. Gerrard, 10/99, based heavily on M. R. Schoeberl’s depiction
Zonal Winds
Zonal Temps
Gravity Waves
(boxes are areas of induced drag)
Planetary Waves
Circulation

4. Atmosphere with Motion
Upper atmosphere with cold summer and warm winter polar mesosphere
Atmosphere with Motion

5. Residual Meridional Circulation
Northern Winter
H.-L. Liu. (2007)

6. λx= 28 km Cg= 40 m/s Ci= 40 m/s λz= 28 km σ~±10 km
Quasi monochromatic gravity waves-ever present
λx= 28 km
Cg= 40 m/s
Ci= 40 m/s
75-
85-
95-
105-
O(1S) O2
Height (km)
λz= 28 km OH
σ~±10 km 10 20 30 40
Horizontal Distance (km)

7. Dispersion Relationship
Wave domain plot, intrinsc phase speed vs horizontal wavelength, versus vertical wavelength

8. Airglow Layers
Vargas et al. (2007)

10. GW Statistics Propagation Direction
Maui, HI
Tang et al. (2005)
Cachoeira Paulista, BR
Vargas (2007), Phd Theses

11. List of References

12. Meridional Propagation Direction Northern Summer

13. Meridional Propagation Direction Northern Summer

14. Meridional Propagation Direction Northern Winter

15. Meridional Propagation Direction Northern Winter

16. Dissipation of GWs (Lidar)
Freely Propagating
Saturated
Damped
Fritts (1984)

17. Dissipation of AGWs (Airglow)
OH O O(1S)
Spatial Series
Cross-Spectra
Amplitude
wave amplitude decreasing with altitude
Vargas et al. (2011), in preparation

18. Modeled MF Divergence Dissipating AGWs
Vargas et al, (2007)

19. Measured Flux Divergence Dissipating AGWs (I’/I ≥ 1%)
Southern Hemisphere
Vargas (2007), Phd Theses

20. Summary
A globally distributed set of ground based observations has been analyzed for the winter and summer directions of wave propagation.
There is experimental evidence that wave forcing is globally significant and opposite to the summer-winter residual meridional flow, predominantly propagating toward the summer pole.
AGW stress acting against the meridional flow imposes a deceleration which biases the magnitude of the meridional circulation (underestimates).